are you sure you dont need the "then" at the end of an if? I thought you had to use the new conditional operator to convert std_logic to a boolean:
if ?? HRST then
..etc
But anyway, the VHDL 2008 supported features are in the quartus manual 10, section 9-10 - VHDL 2008 Support.
As copied from the manual:
The Quartus II software supports the following VHDL 2008 functions:
■ Block comments
■ Simplified sensitivity lists
■ Extensions to generate
■ Matching case statement
■ Matching equality/inequality operators
■ Enhanced bit string literals
■ Unconstrained elements in arrays
So nowhere near the full list!